Though the childhood bone disease rickets has become rare in many countries, the case of one child underscores the potential risk for kids who are allergic to milk.

Reporting in the Annals of Allergy, Asthma & Immunology, Canadian doctors describe the case of a 2-year-old boy with milk allergy who developed rickets due to vitamin D deficiency.

Rickets is a softening and malformation of the bones that arises from deficiency in vitamin D, a nutrient found in a limited number of foods.

Because fortified cow’s milk is a prime source of vitamin D, it’s important for children with milk allergy to get the vitamin from other fortified foods and supplements. This is especially true of children with limited sun exposure, as UV rays trigger the synthesis of vitamin D in the skin.

In the case described in the current report, the boy lived in the less-than-sunny climes of Northern Canada, and he refused to drink fortified soy milk as an alternative to cow’s milk, Dr. Christine T. McCusker, a co-author of the report, told Reuters Health.

Parents of milk-allergic children should be sure to provide alternative sources of vitamin D, such as fortified soy milk or fruit juice, said McCusker, of Montreal Children’s Hospital in Quebec.

Failing that, she added, children should receive calcium and vitamin D supplements. She advised parents to speak with their pediatricians or dietitians to make sure their children are getting adequate amounts of these nutrients to ensure healthy bones.

“Very young children are particularly susceptible,” McCusker noted, “due to their rapid growth and high needs to maintain good bone formation.”

Doctors already advise that babies who are exclusively breastfed receive liquid vitamin D drops, as breast milk contains only small amounts of the nutrient.

According to McCusker, dietary sources of vitamin D are particularly important for children who get little sun for much of the year, and for those with darker skin, who produce less vitamin D from sunlight exposure.

SOURCE: Annals of Allergy, Asthma & Immunology, April 2006.